Devantech multichannel relay module boards devantech usb rly02 the usb rly02 is a relay module board that has relays that provide 2x volt free contact relay outputs that each have a current rating of up to 16a the module is entirely powered and controlled from a standard usb bus and does not require any additional power all relays are spco single pole change over and the normally open normally closed and common pins are all available on the screw terminals for performance monitoring pu